Blogger template grabber4/2/2023 ![]() Push ebx base address of the unpacked PEĬall eax leads to the unpacked PE original entry point Following few calls to VirtualAlloc(), the end of the second unpacking stage can by identified with the following instructions: push 0圆66 magic value checked after unpacking It also involves a small de-obfuscation routine which performs XOR operations with a one byte key (0x0F), used to output decrypted PE sections, within buffers allocated with VirtualAlloc(). The second one is quite simple as well, it implements a small anti-debug trick which reads the 'BeingDebugged' flag within the PEB. The first one is based on the well-known packer UPX and can be easily defeated. ![]() The sample analyzed is packed with 2 layers. Due to the lack of information about this malware, the propagation method of this threat is unknown. Xylitol, a security researcher, has shared a sample of this malware on Virus Total at the end of 2012, but no public analysis seems to be available on the Internet. However, as we will see throughout this blog-post, it is still effective against latest browsers (running in 32-bit mode). The malware is pretty old, its compilation time-stamp points out that it may have been used during November, 2012. In this article I'll try to present a detailed analysis of this malware, with emphasis on the web-browser injection part. Data encryption in SharePoint and OneDriveĪs a new member of the Stormshield Security Intelligence team, my initiation ritual was to analyze a form-grabber malware used to steal passwords thanks to web-browser injection method. ![]()
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